Vapor recovery systems are used in engines to capture fuel vapors, thereby reducing evaporative emission. Fuel vapor recovery canisters, commonly including vapor absorbing carbon, may be used to capture and store the fuel vapor during various times such as during refueling operations. Then, when the engine is running, the fuel vapors may be purged from the canister, and burned, by passing atmospheric air through the canister and into the engine combustion chamber. The air to purge the canister is controlled by a canister purge valve.
A problem exists with canister purge valves in that they can be noisy. One attempt to reduce canister purge valve noise is described in U.S. Pat. No. 6,739,573 to Balsdon. The disclosure attempts to dampen or attenuate undesired noise resulting from the opening and closing of the valve by providing an impact absorbing resilient member to absorb the impact of the valve on a valve seat.
The inventors of the present application have recognized a problem with the above solution. In particular the disclosed attempt does not address a significant contributor to canister purge valve noise. Existing canister purge valves create undesirable air flow noise when they operate. Research work and test data has shown that the air flow noise occurs as the valve opens and closes. The cause of the air noise is the abrupt air pressure change between the valve inlet and outlet as the valves cycles between open and closed. This sound wave travels from the valve outlet to the engine intake manifold.
The inventors herein have discovered a way to disrupt the sound wave as it travels to the intake manifold. Embodiments in accordance with the present disclosure provide a valve outlet design that may prevent the sound wave from traveling directly to the intake manifold. Embodiments may be utilized to break the outlet stream and related sound wave into smaller ones. In this way sound wave intensity may be significantly reduced.
Accordingly, in one example, some of the above issues may be addressed by providing a canister purge valve that may include an inlet port configured to be coupled with an inlet line to receive a fluid from a vapor-recovery canister; and an outlet having two or more exit ports configured to be coupled with a common exit line to pass the fluid to an engine.
In another example, some of the above issues may be addressed by providing a fuel vapor recovery system for an engine. The system may include: a vapor recovery canister arranged in fluidic communication with a fuel tank; an intake manifold in fluidic communication with an engine combustion chamber; and a purge valve configured to control a flow of fluid, the purge valve having an inlet coupled to the fuel tank and an outlet stem with two or more exit ports coupled into a single, common, outlet line leading to the intake manifold.
In still another example, some of the above issues may be addressed by providing a method of operating an engine vapor recovery system. The method may include: routing a purge gas from a canister through a valve to an engine intake manifold; the purge gas may exit the valve from two or more exit ports into a single purge line.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.